Introduction :

pain is a stressor that can threaten homeostasis (a steady

physiological state). The adaptive response to such a stress involves

physiological changes that, in the initial stages, are useful and are also

potentially life-saving(Bultaci, 2007 ).

Unrelieved postoperative pain may result in clinical and psychological

changes that increase morbidity, mortality, costs as well as decrease

quality of life and potentially increase the incidence of chronic pain.

Negative clinical outcomes resulting from ineffective postoperative pain

management include deep vein thrombosis and pulmonary embolism,

coronary ischemia and myocardial infarction, pneumonia, poor wound

healing, insomnia and demoralization. Associated with these

complications are economic and humanistic implications such as

extended lengths of stay, readmissions, and patient dissatisfaction with

medical care. A recent study suggests that pain in ambulatory surgical

patients is still undermanaged and the incidence of moderate to severe

pain remains high (Apfel AL et al., 2003).

We all know that treatment of pain by getting rid of its causes is the

best way, but it is not always possible and especially it does not always

work fast enough. Half of the patients in US consultation rooms come for

the treatment of pain, and no part of pharmacology is better researched

than pain treatment (Barden et al, 2004).

Regional anesthesia and analgesia can be used to significantly

reduce postoperative pain scores and spare the use of systemic opioids.

Regional anesthesia can be performed at the neuraxis (epidural) or the

nerve root (paravertebral). Local anesthetic deposition at these sites will

1

selectively block nerve conduction and result in different analgesic and

side effect profiles . (Linda Le-Wendling, et al., 2015).

The paravertebral block is a selective block of the nerve roots at the

chosen levels. The resultant anesthesia or analgesia is conceptually

similar to a "unilateral" epidural anesthesia. Higher or lower levels can be

chosen to accomplish a band-like segmental blockade at the desired

levels. However, the paravertebral block does not result in

hemodynamically significant sympathetic blockade, therefore,

hypotension is not commonly seen with this block. The lumbar

paravertebral block is used most commonly in our practice for surgical

patients undergoing inguinal herniorrhaphy and lateral abdominal surgery

(Karmakar MK, 2001).

Epidural analgesia can be a useful method of pain management at

various situations. It facilitates early mobilization and also avoids

perioperative pulmonary complications (Sherwood ER et al., 2005).

Evidences for efficacy and safety of ultrasound guided regional

anaesthesia have made it a choice of regional anesthesia in comparison to

the conventional techniques. The use of ultrasound is set as a gold

standard in many institutions practicing regional blocks, and in the near

future, practicing regional anesthesia and intravascular access will need

an ultrasound as standard equipment (Shorten GD and O’Sullivan O,

2010)

Aim of the work2

This prospective randomized single blinded clinical study was

done to evaluate the efficacy of both continuous lumbar epidural

and ultrasound guided continuous paravertebral block on

perioperative analgesia and hemodynamic stability in patients

undergoing lower abdominal surgery.

Anatomy of epidural space:

3

It is an anatomic compartment between the dural sheath and

the spinal canal in some areas it is a real space and in others

only a potential space. It surrounds the spinal part of the dura

and extends from the foramen magnum of the skull above to the

sacral hiatus below. It can be categorized into cervical, thoracic,

lumbar and sacral epidural spaces (Mackintosh, RR.; & Lee,

JA. (1973).

Fig.1 Sagittal section of lumbar vertebrae showing epidural space (Mackintosh, RR.;

& Lee, JA. (1973).

Contents:

It contains the roots of the spinal nerves, the vertebral plexus of veins,

small arteries, lymphatics and the epidural fat. This fat is loose and allows

injected fluid to diffuse through it. The epidural contents are contained in

4

a series of circumferentially discontinuous compartments separated by

zones where the dura contacts the wall of the vertebral canal (Hogan,

1998).

Boundaries:

The space projects through each intervertebral canal to lie behind the

parietal pleura, whose negative pressure is transmitted to it. The epidural

space is bounded superiorly by the fusion of the spinal and periosteal

layers of the dura mater at the foramen magnum. Inferiorly, it is bound by

the sacrococcygeal membrane. The space is bounded anteriorly by the

posterior longitudinal ligament, vertebral bodies and discs while the

pedicles and intervertebral foraminae form the lateral boundary. The

ligamentum flavum, capsule of facet joints and the laminae form the

posterior boundary of the epidural space. (Bromage, 1978).

Measurement of the epidural space: The epidural space is most roomy at the upper thoracic levels. The

epidural space in the adult measures about 0.4 mm at C7-T1, 7.5 mm in

the upper thoracic region, 4.1 mm at T11-12 region and 4-7 mm in the

lumbar region.The space is far greater than that of the subarachnoid space

at the same level. (Nickallis & Kokri, 1986).

Shape and size of the epidural space: These are largely determined by the shape of the lumbar vertebral

canal and the position and size of the dural sac within it. It has been

5

suggested that though merely a potential space it could be up to 5 mm in

depth (Husemeyer & White, 1980).

Pressure of the epidural space: The epidural space with the exception of the sacral region is said to be

under negative pressure. It has been hypothesized that the initial or 'true'

negative pressure encountered when a needle first enters the epidural

space could be due to initial bulging of the ligamentum flavum in front of

the advancing needle followed by its rapid return to the resting position

once the needle has perforated the ligament. The bulging has been

confirmed to occur in fresh cadavers, and pressure studies carried out

during performance of epidural blocks in patients lend weight to this

hypothesis (Zarzur E, 1984).

Negative pressure can be magnified by increasing and reduced by

decreasing the flexion of the spine. The negative pressure appears to be

positive when the vertebral column is straightened. Depending on the

position of the needle, two different components of negative pressure

have been recognized. A basal value ranging from -1 to -7 cmH2O could

be observed when entering the epidural space. It remains stable providing

the patient is well relaxed. An artefactual component up to -30 cmH2O

could appear if needle is further advanced against the dural sac (Usubiaja

et al., 1967).

The epidural space identification is frequently dependent on the

negative pressure within this space. It has been demonstrated that the

epidural pressure is more negative in the sitting position than in the lateral

decubitus position especially in the thoracic region. It therefore suggests

6

that the space is better identified in the sitting position when the hanging

drop technique is used to identify the epidural space (Gil et al., 2008).

Anatomy of the Paravertebral space: The paravertebral space (Figure 2) is a wedge-shaped anatomical

compartment adjacent to the vertebral bodies.( Klein et al., 2004)

described an endoscopic technique that permits imaging of the contents

and boundaries of the paravertebral space in cadavers.  The paravertebral

space is defined anterolaterally by iliopsoas muscle, posteriorly by the

superior costotransverse ligament, medially by the vertebrae and

intervertebral foramina. Within this space, the spinal root emerges from

the intervertebral foramen and divides into dorsal and ventral rami. The

sympathetic chain lies in the same fascial plane and communicates with it

via the rami communicantes. Hence, PVB produces unilateral sensory,

motor and sympathetic blockade.

Figure (2) : - A diagram showing anatomy of paravertebral space and needle insertion. (Mark and John, 2011)

  

7

Contents of the paravertebral space:

The PVS contains adipose tissue within which lie the spinal nerve, the

dorsal ramus, blood vessels, rami communicantes, and anteriorly the

sympathetic chain. The spinal nerves are segmented into small bundles

and lie freely in the adipose tissue of the PVS, which make them

accessible to local anesthetic solutions injected into the PVS.

Communication of paravertebral space:

The lumbar paravertebral space is continuous from L1 to L5 and

for descriptive purposes , the space is split into dermatomes . The PVS

may be divided into anterior and posterior segments by paravertebral

fascia which is a thin fibroelastic structure and may affect the pattern of

spread of local anesthetics during paravertebral block. (Deegan C.A et

al., 2009)

Superior it communicates with the thoracic PVS, there are

conflicting contrast studies in cadavers with regard a

communication between the thoracic and lumbar PVS. Clinically

lumbar plexus block is rarely seen following lower TPVB.

Inferior it communicates with the sacral PVS .

Medial it communicates with the epidural space via the

intervertebral foramina .

The prevertebral fascia lies anterior to the vertebral bodies and can

provide a conduit to the contralateral LPVS for local anesthetic but

this is unusual. (Deegan C.A et al., 2009)

Applied anatomy:

8

Dermatomal innervation :

The lumbar paravertebral block results in anesthesia of the skin of

the posterior, lateral and anterior aspects of the abdomen (L1-L5) .

Myotomal innervation :

The main muscles innervated by the lumbar nerves are the

transversus abdominis muscle, the internal and external oblique muscles

and the rectus abdominis muscle. (Attila et al., 2010) .

Nerves :-

The nerve root passes through its respective intervertebral foramen

to enter the medial aspect of the PVS. There is no fascial sheath covering

the nerve as it emerges as a loose bundle of neurons. This allows for

direct and quick action of local anesthetic on the neurons. Each root

projects a somatic dorsal ramus and a ramus communicantes within the

medial aspect of the PVS. The larger ventral portion passes through loose

areolar tissue and exits the PVS via the corresponding intercostal space.

(Barrett et al., 2004)

9

figure(3):-Relations of paravertebral space and nerves emerging through it (Lönnqvist

and Richardson ,1999)

Sono-anatomy (Ultrasound view of paravertebral space):

Using the traditional approach, locating the paravertebral space can be

technically difficult because it requires location of the transverse process

by blind needle placement and has a failure rate that varies from 8 to

10%. Failure to identify the transverse process results in several needle

redirections causing pain . (Lonnquist et al., 1995).

Sonographic Technique:

There are at least two described approaches to performing an

ultrasound guided PVB:

Classic approach: in which the probe positioned parallel to the

spinal process.

Proximal lateral approach: in which the probe positioned

perpendicular to the spinal process. (Riain et al., 2010).

10

Figure(4) :- Sonoanatomy of paravertebral space, US probe in sagittal

paramedian plane; ( Red line-transverse process). (Attila et al., 2010).

The ultrasound technique also offers the capability to visualize the

needle, the spread of local anesthetic solution and the placement of a

catheter in the paravertebral space under direct vision. (Ben-Ari et al.,

2009).

11

Pain is defined by the International Association for the Study of Pain

(IASP) as "an unpleasant sensory and emotional experience associated

with actual or potential tissue damage, or described in terms of such

damage". Pain is part of the body's defense system, triggering a reflex

reaction to retract from a painful stimulus, and helps adjust behavior to

increase avoidance of that particular harmful situation in the future.

Given its significance, physical pain is also linked to various cultural,

religious, philosophical, or social issues (Rey & Roselyne 2004).

Acute pain begins suddenly and is usually sharp in quality. It serves

as a warning of disease or a threat to the body. Acute pain may be mild

and last just a moment, or it may be severe and last for weeks or months.

In most cases, acute pain does not last longer than six months and it

disappears when the underlying cause of pain has been treated or has

healed. Unrelieved acute pain, however, may lead to chronic pain

(Blumenthal et al., 2005).

Classification of pain

Pain can be categorized according to several variables, including its

duration (acute or chronic), its pathophysiologic mechanisms (nociceptive

or neuropathic), and its clinical context (e.g., postsurgical, malignancy

related, neuropathic, degenerative). Acute pain follows traumatic tissue

injuries, is generally limited in duration, and is associated with temporal

reductions in intensity. Chronic pain may be defined as discomfort

persisting 3–6 months beyond the expected period of healing. In some

chronic pain conditions, symptomatology, underlying disease states, and

other factors may be of greater clinical importance than definitions based

on duration of discomfort. (Vadivelu et al., 2009)

Somatic pain can be further classified as superficial or deep.

Superficial somatic pain is due to nociceptive input arising from skin,

12

subcutaneous tissues, and mucous membranes. It is characteristically well

localized and described as a sharp, pricking, throbbing, or burning

sensation. Deep somatic pain arises from muscles, tendons, joints, or

bones. (Kaikman et al 2007).

The visceral form of acute pain is due to a disease process or

abnormal function of an internal organ or its covering (e.g., parietal

pleura, pericardium, or peritoneum). Four subtypes are described: (1) true

localized visceral pain, (2) localized parietal pain, (3) referred visceral

pain, and (4) referred parietal pain. True visceral pain is dull, diffuse, and

usually midline. It is frequently associated with abnormal sympathetic or

parasympathetic activity causing nausea, vomiting, sweating, and

changes in blood pressure and heart rate. Parietal pain is typically sharp

and often described as a stabbing sensation that is either localized to the

area around the organ or referred to a distant site (Table 1). The

phenomenon of visceral or parietal pain referred to cutaneous areas

results from patterns of embryological development and migration of

tissues, and the convergence of visceral and somatic afferent input into

the central nervous system. Thus, pain associated with disease processes

involving the peritoneum or pleura over the central diaphragm is

frequently referred to the neck and shoulder, whereas disease affecting

the parietal surfaces of the peripheral diaphragm is referred to the chest or

upper abdominal wall(Ready & Edwards 2006).

13

Table 1. Patterns of Referred Pain.

Location Cutaneous Dermatome

Central diaphragm C4

Lungs T2–T6

Heart T1–T4

Aorta T1–L2

Esophagus T3–T8

Pancreas and spleen T5–T10

Stomach, liver, and gallbladder

T6–T9

Adrenals T8–L1

Small intestine T9–T11

Colon T10–L1

Kidney, ovaries, and testes T10–L1

Ureters T10–T12

Uterus T11–L2

Bladder and prostate S2–S4

Urethra and rectum S2–S4

(Ready & Edwards 2006)

Pain pathway:

Nociception is a sequential process that includes transduction of

noxious stimuli into electrical signals by peripheral nociceptors,

conduction of encoded signals by afferent neurons to the dorsal horn of

the spinal cord, and subsequent transmission and modulation of the signals

at both spinal and supraspinal levels. In its simplest form, the nociceptive

pathway is a three neuron chain. (figure 1) The 1st neuron in the chain the

primary afferent neuron is responsible for transduction of noxious stimuli

14

and conduction of signals from the peripheral tissues to neurons in the

dorsal horn of the spinal cord. (Lemke et al., 2004)

Figure (1): Nociceptive pathway (Lemke et al., 2004)

Nociceptive fibers synapse with 2nd order nociceptive neurons in

the dorsal horn of the spinal cord. There are 2 main types of nociceptive

neurons in the dorsal horn (projection neurons and interneurons), and

these neurons are organized into layers or laminae. Neurons that mediate

nociception are located primarily in lamina I (substantia gelatinosa),

lamina II (marginal layer), and lamina V (Figure 2). Projection neurons

are located in laminae I and V and have axons that “project” to supraspinal

3rd-order neurons. Neurons located primarily in lamina I receive input

directly from nociceptive Aδ and C fibers and are called nociceptive-

specific neurons. (Lemke et al., 2004)

The 2nd neuron in the chain - the projection neuron - receives input

from the primary afferent neurons and projects to neurons in the medulla,

pons, midbrain, thalamus, and hypothalamus. Ascending nociceptive

15

tracts, including the spinothalamic, spinobulbar, and spinohypothalamic

tracts, convey nociceptive information from the dorsal horn of the spinal

cord to higher centers in the central nervous system. The spinothalamic

pathway is the major ascending nociceptive pathway; it is divided into

medial and lateral components. The medial component projects to medial

thalamic nuclei and then (via 3rd-order neurons) to the limbic system; it is

responsible for transmission of nociceptive input involved with the

affective-motivational aspect of pain. The lateral component projects to

lateral thalamic nuclei and then to the somatosensory cortex; it is

responsible for transmission of nociceptive input involved with the

sensory-discriminative aspect of pain. The 3rd order, supraspinal neurons

integrate signals from the spinal neurons and project to the subcortical and

cortical areas where pain is finally perceived. (Lemke et al., 2004)

Figure )2(: Dorsal horn neurons. Nociceptive (Aδ and C) and nonnociceptive (Aβ)

fibers(Lemke et al., 2004)

Types of nerve fibers:

Important fibres coming from the periphery into the dorsal horn include:

16

Tiny unmyelinated 'C' fibres that are important carriers of the long-

lasting burning pain that makes a surgical wound (for example)

such an unpleasant experience.

Thin myelinated 'A delta' fibres, concerned with more accurate

localisation of pain, and terminating mostly laterally in laminae I

and V.

Rather chunky 'A beta' fibres that carry information about vibration

and position sense from the periphery to the cord.

Unpleasant stimuli entering via the C fibres can be suppressed by

concurrent stimulation of A delta fibres (high amplitude low frequency

stimulation, for example by acupuncture) or by impulses passing through

A beta fibres. Examples of the latter include TENS (transcutaneous

electrical nerve stimulation) and the simple expedient of rubbing the skin,

which is well known by mothers to decrease perception of pain (Lemke et

al., 2004) .

Nociceptors:

Most nociceptors are free nerve endings that sense heat and

mechanical and chemical tissue damage. Types include (1)

mechanonociceptors, which respond to pinch and pinprick, (2) silent

nociceptors, which respond only in the presence of inflammation, and (3)

polymodal mechanoheat nociceptors. The last are most prevalent and

respond to excessive pressure, extremes of temperature (> 42°C and <

18°C), and alogens (pain-producing substances) (Westlund et al., 2007).

Nociceptors are present in both somatic and visceral tissues. Primary

afferent neurons reach tissues by traveling along spinal somatic,

sympathetic, or parasympathetic nerves. Somatic nociceptors include

17

those in skin (cutaneous) and deep tissues (muscle, tendons, fascia, and

bone), whereas visceral nociceptors include those in internal

organs(Westlund et al., 2007).

Chemical Mediators of Pain:

Neurotransmitters are chemicals that allow the movement of

information from one neuron across the gap between it and the adjacent

neuron. The release of neurotransmitters from one area of a neuron and

the recognition of the chemicals by a receptor site on the adjacent neuron

causes an electrical reaction that facilitates the release of the

neurotransmitter and its movement across the gap (Thomas et al., 2005).

Several neuropeptides and excitatory amino acids function as

neurotransmitters for afferent neurons subserving pain (Table 2). Many if

not most neurons contain more than one neurotransmitter, which is

simultaneously coreleased. The most important of these peptides are

substance P (sP) and calcitonin gene-related peptide (CGRP). Glutamate

is the most important excitatory amino acid (Schaefer et al., 2006).

Table 2. Major Neurotransmitters Mediating or Modulating Pain.

Neurotransmitter Receptor1

Effect on Nociception

Substance P NK–1 Excitatory

Calcitonin gene-related peptide Excitatory

Glutamate NMDA, AMPA, kainite, quisqualate Excitatory

Aspartate NMDA, AMPA, kainite, quisqualate Excitatory

Adenosine triphosphate (ATP) P1, P2 Excitatory

18

Somatostatin Inhibitory

Acetylcholine Muscarinic Inhibitory

Enkephalins , , Inhibitory

-Endorphin , , Inhibitory

Norepinephrine 2

Inhibitory

Adenosine A1

Inhibitory

Serotonin 5-HT1 (5-HT3)

Inhibitory

-Aminobutyric acid (GABA) A, B Inhibitory

Glycine Inhibitory

(Schaefer et al., 2006).

As important as the ascending pathways are fibres that descend from

brainstem to spinal cord to modulate the incoming signals. Notable

neurotransmitters mediating this anti-nociceptive effect include nor

adrenaline (nor epinephrine), especially in the locus coeruleus, and

serotonin in the raphe nuclei. Opioid receptors are prevalent here. Some

descending connections are:

19

Fig.3 Descending

connections that modulate incoming pain impulses. (Sutin & Carpenter 2004).

Incoming painful stimuli are transmitted (A) to the dorsal horn, and

from there (B) to the periaqueductal grey (PAG). Descending impulses

pass (C) to the raphe nuclei, especially the nucleus raphe magnus, in the

upper medulla, and thence back to the dorsal horn via reticulospinal fibres

(D). The above shows only the serotonergic descending fibres. Other

pain-suppressing impulses pass from the PAG to the locus coeruleus, and

from there to the dorsal horn. (Sutin & Carpenter 2004).

Assessment of Acute Pain

Based on the assumption that patient self-reporting is the "most reliable

indicator of the existence and intensity of pain” the ideal tool for pain will

identify the presence of pain and its evolution over time. In addition, tools

should be applicable to any person regardless of age, race, creed,

socioeconomic status, and psychological or emotional background

(Rowbotham & Macintyre 2003).

Assessment of pain in adults:

20

In the assessment of pain intensity, rating scale techniques are often

used. The most commonly used forms are:

 • The Category Rating Scales: (e.g. none, mild, moderate, severe,

unbearable or 1-5).

• The Visual Analogue Scales (VAS): (e.g. 10 cm line with anchor points

at each end). The VAS has been shown to be more sensitive to change

and is therefore more widely used. These scales may also be incorporated

into pain diaries.

 • McGill Pain Questionnaire (MPQ): (78 pain adjectives arranged into 20

groups further arranged into sets of words describing sensory aspects of

the quality of pain). Very widely used questionnaire.

(Svensson et al., 2007).

A Visual Analogue Scale (VAS) is a measurement instrument that tries

to measure a characteristic or attitude that is believed to range across a

continuum of values and cannot easily be directly measured.

Figure (4): Visual analogue scale (VAS) ,Verbal rating scale (VRS) and Numerical

rating scale (NRS), (Breivik et al., 2000)

Operationally a VAS is usually a horizontal line, 100 mm in length,

anchored by word descriptors at each end, as illustrated in Fig. 1. The

21

patient marks on the line the point that they feel represents their

perception of their current state. The VAS score is determined by

measuring in millimetres from the left hand end of the line to the point

that the patient marks. There are many other ways in which VAS have

been presented, including vertical lines and lines with extra descriptors.

(Niven & Dowens 2000).

Assessment of acute pain during movement (dynamic pain):

Assessment of the intensity of acute pain at rest after surgery is

important for making the patient comfortable in bed. However, adequate

relief of dynamic pain during mobilization, deep breathing, and coughing

is more important for reducing risks of cardiopulmonary and

thromboembolic complications after surgery. Immobilization is also a

known risk factor for chronic hyperalgesic pain after surgery, becoming a

significant health problem in about 1%, a bothersome but not negligible

problem in another 10%. Effective relief of dynamic pain facilitates

mobilization and therefore may improve long-term outcome after surgery.

(Jarzyna et al., 2011).

Management of acute postoperative pain:

Opioid Monotherapy:

Opioids have been used as analgesics for more than 2,000 years and

continue to be a key element in moderate to severe acute postoperative

pain management. However, opioid-only treatment plans can result in

intolerable and dangerous adverse effects, including constipation, nausea

and vomiting, excessive sedation, and respiratory depression. Concerns

are also being raised about a possible link between opioid-only treatment

plans and a paradoxic clinical situation in which increasing doses of

22

opioid result in increasing sensitivity to pain, a condition referred to as

opioid-induced hyperalgesia ( Pasero, 2011).

Adverse effects associated with opioids commonly occur and can

prevent patients from experiencing satisfactory analgesia. In a systematic

review analyzing opioid-induced adverse effects among postoperative

patients in 45 randomized-controlled studies, 31% of patients experienced

an adverse gastrointestinal (GI) event (ileus, nausea, vomiting,

constipation), 30.3% of patients reported an adverse central nervous

system (CNS) event (somnolence, sedation), 18.3% of patients reported

pruritus, 17.5% of patients experienced urinary retention, and 2.8% of

patients had respiratory depression (Wheeler et al., 2002).

Non-steroidal anti-inflammatory drugs (NSAIDs):

NSAIDs are considered to be appropriate for mild to some moderate-

intensity acute pain and as adjuncts to opioids for the relief of more severe

acute pain. They do not produce respiratory depression or impair GI

motility so are considered an important component with acetaminophen in

a multimodal treatment plan for acute pain. (Pasero et al., 2011).

The analgesia and anti-inflammatory effects induced by NSAIDs

are the result of cyclo-oxygenase 2 (COX-2) inhibition, while the adverse

effects of NSAIDs are generally the result of COX-1 inhibition. For

example, an adverse effect of COX-1 inhibition is reduced platelet

aggregation. The most common adverse effect of NSAIDs is gastric

complications, and patients with a history of peptic ulcer disease are

among the highest risk for this adverse effect. NSAIDs can also induce

acute renal failure, particularly in patients with acute or chronic volume

depletion, cardiac failure, liver cirrhosis, ascites, diabetes, or preexisting

hypertension. (Pasero et al., 2011)

23

Acetaminophen:

Because of its efficacy, safety, lack of clinically significant drug

interactions, and lack of the adverse effects associated with other

analgesics, IV acetaminophen is an attractive component of a multimodal

analgesic treatment plan. (Groudine et al., 2011)

Acetaminophen is not associated with the increased incidence of

nausea, vomiting, and respiratory depression that can occur with opioids,

or the platelet dysfunction, gastritis, and renal toxicity that are sometimes

associated with NSAIDs. (Silvanto et al., 2007)

Gabapentin and pregabalin:

Gabapentin first marketed in the nineties for its antiepileptic properties,

is known to be effective in treating chronic neuropathic pain, complex

regional pain syndromes, and restless legs syndrome. Gabapentin is

believed to act on a specific receptors, which are over expressed in the

dorsal horn of the spinal cord and in spinal ganglia in cases of

neurological injury. The advantages of gabapentin are that it does not

interact with haemostasis and does not induce respiratory depression.

Further, its anxiolytic properties can be useful preoperatively.

Recommended dosages are (300 to 3200 mg/day) in 2-3 doses.

Bioavailability of gabapentin is 36% to 60% and decreases with the

ingested dose because of good absorption at the small intestine level.

Gabapentin is not metabolized and is eliminated in the urine; therefore,

dosages should be modified in renal failure. Side effects are rare and

usually mild: dizziness,vertigo, headaches, nausea, vomiting, and

ataxia(Fassoulaki et al.,2006)

24

Regional Anesthesia and local anesthetics:

Regional anesthesia is used to desensitize a specific part of the body

to a painful stimulus.  It is classified into six sites of placement of local

anesthetic: topical or surface anesthesia, local infiltration, peripheral nerve

block, intravenous regional anesthesia, epidural anesthesia, and spinal

(subarachnoid) anesthesia. (Stoelting et al., 2006).

Regional anesthesia techniques may include, but are not limited to,

spinal, epidural, peripheral nerve blocks, upper and lower extremity

blocks, airway blocks, and transversus abdominis plane (TAP) blocks. 

Regional anesthesia techniques may be used alone, or in combination with

other anesthetic techniques, to provide anesthesia and analgesia for a

variety of surgical and obstetrical procedures as well as for chronic pain

management.  Using regional anesthesia in combination with other

anesthetic techniques can minimize side effects of an individual anesthetic

technique, maximize benefits, and offer the patient options in the selection

of anesthesia and analgesia. (Olson et al., 2010)

Multimodal Pain Management

To address the under-treatment of postoperative pain and the

limitations of opioid monotherapy, a strategy known as multimodal pain

management was introduced in the early 1990s . This approach

simultaneously administers two or more analgesic agents with different

mechanisms of action. Combination therapy using drugs with distinct

mechanisms of action may add analgesia or have a synergistic effect and

allow for better analgesia with the use of lower doses of a given

medication than if the drug was used alone (Pasero, 2011). For example,

postoperative multimodal analgesia may consist of the use of opioid and

non-opioid pharmacologic agents, as well as regional anesthesia and

25

continuous peripheral nerve block. The multimodal approach has been

used by many professional organizations, including the American Society

of Anesthesiologists (ASA) and the American Pain Society (APS)

(Jarzyna et al., 2011).

Ultrasound guidance has greatly influenced the practice of regional

anaesthesia in the last 15 years. Between 1884, the year when Carl Koller

performed the first regional block for eye surgery in Vienna, and the late

1970s, the main developments were in new local anaesthetic drugs and

the introduction of mainly anatomical methods for nerve identification.

Unfortunately, anatomy is not exactly predictable and the natural

variability of human anatomy led to poor success rates for many

peripheral nerve blocks. (Kapral et al., 1994)

Current ultrasound equipment allows much easier identification of very

small neural structures than it was possible with machines introduced

only a few years ago. In addition, adjacent anatomical structures can be

identified. (Duggan et al., 2009)

Without any doubt, direct visualization of neural and adjacent

anatomical structures is the main advantage of the use of ultrasound for

regional block techniques. An important objective for ultrasound is

visualization of the spread of local anaesthetic during injection.

Confirmation of the correct disposition of local anaesthetic avoids any

maldistribution , such as epineural, perineural or intravascular injection.

In addition, an ability to perform blocks with small volume of local

26

anaesthetic is mainly based on an ability to observe the spread of the local

anaesthetic directly (Latzke et al., 2010).

Basic of ultrasound physics:-

Ultrasound is a form of mechanical sound energy that travels through a

conducting medium (e.g., body tissue) as a longitudinal wave producing

alternating compression (high pressure) and rarefaction (low pressure).

Sound propagation can be represented in a sinusoidal waveform with a

characteristic pressure (P),wavelength (λ), frequency (f), time (T) and

velocity (speed (c) + direction) (Figure-1). (Edler and Lindstrom, 2004)

)Figure -1 :(ultrasound waves, High-frequency probes produce shorter wavelength waves, and low-frequency probes produce longer wavelength waves(Edler and

Lindstrom, 2004)

Tissue appearance under ultrasound:

*Hyperechoic areas :- have a great amount of energy from returning

echoes and are seen as white.

*Hypoechoic areas: - have less energy from returning echoes and are

seen as gray.

27

*Anechoic areas without returning echoes are seen as black.

Ultrasound waves and tissue interaction:

The speed of ultrasound waves through biological tissue is based on

the density of tissues, and not the frequency of the ultrasound waves.

The greater the tissue density, the faster the ultrasound waves will

travel. The image processor in the ultrasound machine assumes that the

ultrasound waves are travelling through soft tissue at a velocity of

1,540 m/sec. Three things can happen to ultrasound waves as they

travel through tissue reflection, attenuation, and refraction. (Weyman,

1994)

1-Reflection:

The generation of ultrasound images is dependent on the energy of

the echoes that return to the probe. The amount of reflection of

ultrasound waves is dependent on the difference in acoustic impedance

at the interface between different tissues. Acoustic impedance is the

resistance of a material to the passage of ultrasound waves. (Figure -2).

The greater the difference in acoustic impedance at tissue interfaces,

the greater the percentage of ultrasound waves that is reflected back to

the probe to be processed into an image.(Middleton et al., 2004)

28

(Figure -2): Specular reflection vs. scattering reflection.(Middleton et al.,

2004)

2-Attenuation:

Attenuation of ultrasound waves is dependent on three factors:

Attenuation coefficient of the tissue.

Distance travelled.

Frequency of the ultrasound waves.

Attenuation is inversely related to frequency; the higher the frequency

of the ultrasound wave, the greater the attenuation. Therefore, high

frequency probes have less tissue penetration due to greater

attenuation, which makes imaging of deeper structures difficult with

high-frequency probes.(Jespersen,1998)

3-Refraction:

When the acoustic impedance between tissue inter faces is small,

the ultrasound wave’s direction is changed slightly at the tissue

interface, rather than being reflected directly back to the probe at the

inter face this is analogous to the bent appearance of a fork in water,

which is caused by refraction of light waves at the air/water inter face.

Refracted waves may not return to the probe in order to be processed

into an image. Therefore, refraction may contribute to image

degradation (Figure -3).(Otto, 2000)

29

(Figure-3): Refraction vs. reflection.(Otto, 2000)

Resolution: It is the ability to distinguish two close objects as separate, is very

important in ultrasound-guided regional anaesthesia. There are two

types of resolution:

Axial resolution.

Lateral resolution.

1-Axial resolution:

Axial resolution is the ability to distinguish two objects that lie

in a plane parallel to the direction of the ultrasound beam. Axial

resolution is equal to half of the pulse length. Higher frequency probes

have shorter pulse lengths, which allows for better axial resolution.

The ultrasound probe emits ultrasound waves impulses, not

continuously. These pulses of ultrasound waves are emitted

intermittently as the probe has to wait and listen for the returning

echoes.(Chan, 2009)

2-Lateral resolution:

Lateral resolution is the ability to distinguish two objects that lie

in a plane perpendicular to the direction of the ultrasound beam.

Lateral resolution is related to the ultrasound beam width, the more

narrow (focused) the ultrasound beam width, the greater the lateral

resolution. High frequency probes have narrower beam widths, which

allows for better lateral resolution. Poor lateral resolution means that

two objects lying side by side may be seen as one object. The position

30

of the narrowest part of the beam can be adjusted by changing the focal

zone.(Chan, 2009).

Ultrasound machine controls:

1-Depth:

The depth of tissue imaged can be adjusted on the machine and

relates to the type of probe being used. Low-frequency probes will be

able to image deeper tissue depths than high-frequency probes. With a

linear array probe, as the depth is increased, the image on the screen

will appear narrower and structures will appear smaller, but the width

of the field of view is relatively constant. Notice that the field of view

is constant from 3 cm to 6 cm but at 2 cm it has decreased. (Kossoff,

2000)

(Figure -4) :-General Electric (GE) ultrasound portable device control pannel

2-Frequency:

Variable-frequency probes allow changes in frequency within a

narrow range. An 8 to 13 MHz probe allows selection of frequency

between 8 and 13 MHz. The lower frequencies are used for deeper

31

structures and the higher frequencies are used for more superficial

structures. Select a frequency that balances penetration and resolution.

(Lawrence, 2007)

3-Gain:

Ultrasound probes transmit ultrasound waves 1% of the time and

spend the remaining 99% of the time listening for the returning echoes.

Increasing the gain increases signal amplification of the returning

ultrasound waves, in this way the gain function can be used to

compensate for loss of energy due to tissue attenuation. Returning

ultrasound waves are referred to as “signal” while background artifact

is referred to as “noise”. Increasing the gain increases the signal-to-

noise ratio. However, if the gain is increased too much, the screen will

have a “whiteout” appearance and all useful information is lost.

(Lawrence, 2007).

4-Color-flow Doppler:

Color-flow Doppler allows for detection of flow within vascular

structures. Moving objects, such as red blood cells (RBCs), affect

returning ultrasound waves differently than stationary objects. Color-

flow Doppler can differentiate between RBCs moving away from the

probe and RBCs moving towards the probe. Red blood cells moving

towards the probe will return ultrasound waves at a higher frequency

and are displayed as red; RBCs moving away from the probe will

return ultrasound waves at a lower frequency and are displayed as blue.

(Figure-5)(Otto,2000).

32

(Figure -5): Radial artery flow is seen as red when the probe is tilted towards the

direction of flow.(Otto, 2000).

5-Pulse-wave Doppler:

Pulse-wave Doppler provides flow data from a small area along

the ultrasound beam. The area to be sampled can be selected by the

operator. Once pulse-wave Doppler is selected, the image is frozen and

the operator selects the area to be sampled. The pulse-wave

information is displayed graphically at the bottom of the screen as well

as heard(figure -6).(Otto, 2000)

)Figure -6 :(Pulse-wave Doppler showing arterial flow in the femoral artery.(Otto, 2000)

33

Needle insertion:

1-In plane (IP)

The needle is inserted in the same plane as the ultrasound beam.

The goal is for the path of the needle to be entirely within the beam of

the ultrasound. The more parallel the needle is to the probe (shallower

angle of insertion) the easier the needle will be to visualize. When

inserting the needle, the goal is to be as close to parallel to the probe as

possible. Since with many blocks it will be impossible for the needle to

be parallel to the probe, the goal should be to have as shallow an angle

of insertion as possible. In order to achieve a shallow angle between

the needle and the probe, some blocks will require that the needle be

inserted a greater distance from the probe as opposed to right next to

the probe.(Chan, 2009)

2-Out of plane (OOP):

The needle is perpendicular to the beam of the ultrasound. The

needle is seen as a small hyperechoic dot on the screen. In an OOP

approach, the needle needs to travel a shorter distance to the target than

in-plane approach. For those making the transition from nerve

stimulation to ultrasound, the location of needle insertion in the OOP

approach is similar to the traditional nerve stimulator insertion points.

Finding the needle tip in an OOP approach can be challenging for the

beginner. The steeper the angle of insertion, the easier to see the needle

in an OOP approach.(Chan, 2009).

Advantages of ultrasound guided nerve block

 Ultrasound guidance offers several potential advantages:

34

1- Direct visualization of nerves: This may replace other methods of

nerve localization, such as electrical stimulation or paraesthesia.

2- Direct visualization of anatomical structures: vessels, muscles,

bones, fascia tendons: This may help assess individual variations in

anatomy and facilitate identification of nerves.

3- Real-time control of needle advancement: This may reduce the

number of needle passes, shorten the block performance time and

lower the risk of complications caused by a needle e.g., vascular

puncture, neuropraxia or pneumothorax.

4- Assessment of LA spread around the nerves and immediate

supplementary injections in case of insufficient spread: This may

improve block effectiveness, shorten latency, prolong duration, allow

LA dose reduction and lower the risk of overdose.

5- Avoidance of muscle twitches: This may reduce block discomfort.

(Marhofer P., et al., 2005) .

35

Technique of epidural block:Patient position:

Epidural block can be performed in the lateral or sitting position. when

the spinous processes are not easily palpable, the sitting position is preferred.

In some patients, the sitting position may be associated with orthostatic

hypotension and syncope. For this reason, it is important for an assistant to

provide continuous support to the patient during the procedure. (Andrews et

al, 1993).

Methods of identification of the epidural space: Various methods have been used in identifying the epidural space.

Most of these traditional methods of locating the epidural space depend

on the negative pressure exhibited during the introduction of the epidural

needle into the space. Any techniques identifying the epidural space

should be simple and straightforward, effective, safe, and reliable to

minimize the number of complications associated with it (Nafiu &

Bullough, 2007).

36

1) loss of resistance (LOR) technique: It is One of the most reliable methods in identifying the space.it

depends on loss of resistance (LOR). This method of identification uses

either air or a liquid such as saline or a local anesthetic to achieve it. The

technique applies continuous or intermittent pressure on the piston of an

epidural glass or plastic syringe towards the barrel, and the loss of

resistance is where it becomes possible to inject through the syringe

attached to the epidural needle, so the piston can easily move into the

barrel. This technique works because the ligamentum flavum is extremely

dense, and injection into it is almost impossible. The syringe may contain

air or saline. The principles are the same, but the specifics of the

technique are different due to the greater compressibility of air with

respect to saline or lidocaine.

The identification of the epidural space with LOR to air has been found

to be more difficult and caused more dural punctures than with lidocaine

or air plus lidocaine techniques. Additionally, sequential use of air and

lidocaine had no advantage over lidocaine alone (Evron et al., 2004).

The techniques of LOR to air or saline are also associated with some

complications. While LOR to air has been linked to paraplegia and

pneumocephalus (Nay et al., 1993). LOR to saline is frequently

associated with dilution of the injected local anesthetic (Okutomi &

Hoka, 1998).

2) modified drip method:

In this method, a saline infusion was prepared, leaving the distal 40 cm

of infusion tubing full of air, and then attached to the hub of a Tuohy

needle. Accurate identification of the epidural space was accomplished in

less than one minute in 95% of cases. This technique showed some

37

advantages over the hanging drop and the manual loss of resistance

techniques. (Michel & Lawes,1991).

3) Membrane in Syringe technique: This is a modification of the loss of resistance technique for

identifying the epidural space during epidural anesthesia. A plastic

membrane is placed halfway inside a syringe dividing the syringe into

two compartments. The saline compartment encompasses the nozzle of

the syringe (the distal compartment). The plunger is installed in the

opposite half of the hallow cylinder. Air is trapped in the space between

the membrane and the rubber plunger (air compartment).(Lin et al.,

2002).

4) Macintosh epidural balloon: Though cost implication of the use of epidural balloon is more than the

LOR to air, it obviously offered better advantage over the traditional use

of air.

5) The use of epidrum:_ This device is designed to operate at a high enough pressure to

discharge into the epidural space but a low enough pressure to minimize

premature leaking into the patients' tissues. The optimal pressure is

generated by the extremely thin diaphragm on top of the device that acts

as the meniscus of a manometer, so allowing the operator to interpret the

diaphragm's signal to identify the position of the tip of the needle.

Epidrum has been known to offer the following benefits:

Relatively simple. The trainer can monitor the signal when the trainee

is performing the procedure.

It is safe, effective and reliable.

38

It allows the use of a smaller needle to: reduce post dural puncture

headache and reduce epidural haematoma formation.

It offers a visual endpoint

Optimised, low, constant pressure - minimizes false positive error.

Easily observed cerebral spinal fluid (CSF) in the event of a dural

tap(Samada et al .,2011).

Fig.1:midline vs. paramedian approach of epidural block(Balki et al, 2009)

Contraindications:

Absolute contraindications include patient refusal, lack of adequate

equipment, lack of expertise or supervisory staff, severe coagulopathy,

and infection at the site of puncture. Some patients may be technically

challenging because of previous back surgery, such as lumbar fusions and

Harrington rods.

39

Relative contraindications include low platelet count with no

coagulopathy, infection remote from the site of lumbar puncture,

progressive neurologic disease, increased intracranial pressure,

hypovolemia and low fixed cardiac output e.g. sever aortic stenosis(Silva

and Halpern, 2010).

Complications:

Complications of central neuraxial blockade, much depending on the

experience in patient management, as well as materials, equipment, and the

presence of risk factors, have been reported to occur at various frequencies

(Moen et al, 2004).

Neurological complications resulting from accidental penetration of the

dura are similar to those that occur with spinal anesthesia. Inadvertent dural

puncture and postdural puncture headache, direct neural injury, total spinal

anesthesia, and subdural block have been commonly reported.

1) Inadvertent dural puncture and postdural puncture

headache:

The incidence of inadvertent dural puncture ranges between 0.19–0.5%

of epidural catheter placements. Postdural puncture headache (PDPH),

described as a positional, bilateral frontal-occipital, nonthrobbing pain, may

develop in as much as 75% of patients (Van de Velde et al, 2008).

2) Direct neural injury:

Direct neural injury has a reported incidence of 0.006%, and has been

associated with paresthesias during needle placement and pain on injection

(Ruppen et al, 2006).

40

3) Total spinal anesthesia:

Total spinal anesthesia may occur if the solution used for epidural

anesthesia is inadvertently administered into the intrathecal space in large

volumes. Symptoms are of a rapidly arising subarachnoid block, potentially

resulting in cardiovascular collapse and apnea requiring prompt

resuscitation. Provided that immediate, skilled resuscitative efforts are made,

complete recovery should be expected (Hara and Sata, 2006).

4) Epidural Hematoma:

Hemorrhagic complications are serious adverse outcomes that may

arise from neuraxial anesthesia. Epidural hematoma is a rare, but potentially

devastating, complication that requires emergency decompression in case of

clinical deterioration. It is rarely attributed to an arterial source, and can

develop spontaneously (Horlocker, 2004).The risk is reported to increase

15-fold when there is a concomitant use of anticoagulants, and appropriate

precautions are not taken. Appropriate timing of anticoagulant

administration is important in decreasing the risk of bleeding (Horlocker et

al, 2010).

5) Epidural catheter related infections:

Epidural abscess and meningitis has been reported to occur in 1: 1000

and 1: 50,000 catheter placements, respectively.The classic presentation

signs and symptoms are severe midline back pain, fever, and leukocytosis,

with or without neurological symptoms (worsening lower limb weakness and

paraplegia, incontinence, irradiating pain, nuchal rigidity, and headache).

Symptoms commonly appear after removal of the epidural catheter (Christie

and McCabe, 2007).

6) Pruritis:

41

Pruritis is the most common side effect of neuraxial analgesia. The

incidence and severity is dependent on the opioid dose, and is more frequent

with intrathecal opioids than with epidural opioids (58% versus 30%). The

cause of pruritus is not well understood, but it is unlikely to be related to

histamine release. Antihistamines, often prescribed to treat pruritus after

neuraxial opioids, are usually ineffective. There is increasing evidence that

neuraxial opioid-induced pruritus is mediated through central μ-opioid

receptors. Opioid antagonists (e.g. naloxone) or partial agonist-antagonists

(e.g. nalbuphine) are effective in relieving pruritus (Herman et al, 1999).

7) Nausea and Vomiting:

With an estimated incidence of 17% to 35%, nausea and vomiting may

occur as the opioid diffuses from the site of the epidural injection to the

chemoreceptor trigger zone for vomiting located in the 4th ventricle (Bragg,

1998). This side effect usually occurs 4 to 6 hours after administration and

may be associated with activity, such as turning and coughing (Naber et al,

2009).

8) Urinary Retention:

It usually occur in the first 24 to 48 hours and then resolves

spontaneously. Signs and symptoms include a lack of urge to void and

bladder distention. The underlying mechanism may be the action of the

narcotic on the spinal nerves innervating the detrusor muscle, thereby

altering bladder tone (atonia) and predisposing to bladder over distension

and increased residual volumes. For unknown reasons, urinary retention

occurs more often in elderly men, patients with pre-existing bladder

disorders, and during pregnancy and the postoperative period.Many centers

insert an indwelling Foley catheter for the duration that the epidural catheter

remains in place. If a Foley catheter is not used, intermittent catheterization

42

may be necessary. However, catheterization in some populations may in fact

further increase the risk of infection (Lingaraj et al, 2007).

9)Hypotension:

Hypotension is a second potential narcotic-related side effect of

epidural analgesia. However, as epidural narcotics have a localized action

and do not produce sympathetic nervous system blockade, they generally

have little effect on blood pressure. The hypotensive state may be a result of

fluid volume changes or immobility postoperatively, in which case IV fluids

are indicated.Local anesthetics are not specific to sensory afferent fibers, and

they do block autonomic and motor efferent fibers. This sympathetic

blockade can lead to hypotension and exacerbate or intensify postural

hypotension due to hypovolemia. As a result, postural hypotension may

restrict early ambulation and potentially increase morbidity. Therefore,

assessment of the patient's motor strength prior to ambulation is

critical (Roffey et al, 2001).

10) Respiratory Depression:

The most serious narcotic-related side effect associated with epidural

analgesia is respiratory depression. It is manifested by a decrease in the

depth of respirations or tidal volume, followed later by a decrease in

respiratory rate. Initially, the patient may be able to maintain an adequate

respiratory rate but the hyperventilation that occurs does not allow adequate

oxygen CO2 exchange. This impaired gas exchange leads to mental status

43

changes indicative of increasing CO2 levels. Therefore, a decrease in the

patient's level of consciousness or arousability is considered the first and the

best indicator of respiratory depression (Wild, 1990).

Technique of paravertebral block:

Manoj K. Karmakar, MD; Anthony M-H. Ho, MD lumbar

paravertebral block (lPVB) is the technique of injecting local anesthetic

alongside the lumbar vertebra close to where the spinal nerves emerge

from the intervertebral foramen. This produces unilateral, segmental,

somatic, and sympathetic nerve blockade, which is effective for

anesthesia and in treating acute and chronic pain of unilateral origin from

the abdomen. Hugo Sellheim of Leipzig (1871–1936) is believed to

have pioneered lPVB in 1905. Kappis, in 1919, developed the technique

of paravertebral injection, which is comparable to the one in present-day

use. Although paravertebral block was fairly popular in the early 1900s, it

seemed to have fallen into disfavor during the mid and later part of the

century, the reason for which is not known. In 1979 Eason and Wyatt

rekindled interest by describing a technique of paravertebral catheter

placement. Our understanding of the safety and efficacy of lPVB has

improved significantly in the last 25 years, and there has been a gradual

renewal of interest in this technique. Currently it is used not only for

analgesia but also for surgical anesthesia, and its application has been

extended to children(Kirchmair et al., 2001)

Classic method:

44

The classic insertion technique for PVB is percutaneous and has been

described by Eason and Wyatt. Similar to epidural insertion, loss of

resistance is felt immediately after puncturing the superior

costotransverse ligament, which represents the posterior border to the

paravertebral space. Approximately 2.5 cm lateral to the midline of the

spine, the transverse process is touched and a needle is directed over

(commonly) or under the boney landmark no more than 1 cm and local

anesthetic with or without a catheter is inserted. The skin to paravertebral

distance is, on average, 5.5 cm. The technique is also perfectly described

by Hounsell. Percutaneous insertion has a failure rate of 10%.

Ultrasound guided technique:a)Transverse scan :

With this scanning technique,the transducer is positioned 4 to 5 cm

lateral to lumbar spinous processes at the L3-L4 level and directed

slightly medially to assume a transverse oblique orientation.This

approach allows imaging of lumbar paravertbral region with the erector

spinae muscle, psoas major muscle, quadratous lumborum muscle,

transverse process and the anterolateral surface of vertebral body.In the

transverse oblique view,the inferior vena cava(IVC) On right sided scan,

or the aorta, on the left-sided scan, also can be seen and provide

additional information on the location of the psoas muscle, which is

positioned superficial to these vessels. In this view, the psoas muscle

appears slightly hypoechoic with multiple hyperechogenic striations

within. The lower pole of the kidney can often be seen, when scanning at

the L2-L4 level, as an oval structure that ascends and descends with

respirations(Gadsden JC et al., 2008). The key to obtaining adequate

images of the psoas muscle and lumbar paravertebral space with the

45

transverse oblique scan is to insonate between two adjacent transverse

processes. This scanning method avoids acoustic shadow of the

transverse processes, which obscures the underlying psoas muscle and the

intervertebral foramen (angle between the transverse process and

vertebral body) and allows visualization of the articular process of the

facet joint (APFJ) as well. Because the intervertebral foramen is located

at the angle between the APFJ and vertebral body, lumbar nerve roots

often can be depicted.(Farny j et al., 1994)

A

B C

Figure 2: (A) Ultrasound anatomy of the lumbar paravertebral space using transverse oblique view. SP, spinal process; ESM, erectors spinae muscle; QLM,

46

quadratus lumborum muscle; PsMM, psoas major muscle; VB, vertebral body. The lumbar plexus root is seen just below the lamina as it exits the interlaminar space and enters into the posterior medial aspect of the PsMM. (B) Needle path in ultrasound-guided lumbar paravertebral block using transverse oblique view. LP, lumbar plexus; PsMM, psoas major muscle; VB, vertebral body. (C) Spread of the local anesthetic solution . Due to the deep location of the space, spread of the local anesthetic may not always be well seen. Color Doppler imaging can be used to help determine the location of the injectate.(Cowie B et al., 2010)

b)Paramedial sagittal scan:

Kirchmair and colleagues suggested a paramedial sagittal scan

technique with transverse scan to delineate the psoas major muscle at the

L3-L5 level with the patient in the lateral position. Once a satisfactory

image is obtained, the needle is inserted in-plane medial to the transducer

approximately 4 cm lateral to the midline. Then the needle is advanced

until the correct position is confirmed by obtaining a quadriceps motor

response to nerve stimulation (1.5-2.0 mA). Needle-nerve contact and

distribution of the local anesthetic is not always well seen, although nerve

roots may be better visualized after the injection. Injection, dosing, and

monitoring principles are the same as with the nerve stimulator-guided

technique(Doi et al., 2010).

47

Figure 3: Ultrasound image of the lumbar

paravertebral space demonstrating the

complex anatomy of the region. LP,

lumbar plexus; VB, vertebral body. Power

Doppler ultrasound is capturing the flow

in the inferior vena cava (IVC). The right

kidney is also visualized.

 

Figure 4: Transverse image of lumbar

paravertebral space demonstrating

sacrum and transverse process (TP) of L5.

Starting the scanning process from the

sacral area and progressing cephalad

allows the identity of the individual

transverse processes (levels). As the

transducer is moved cephalad and the

surface of the sacrum disappears, the next

osseous structure that appears is the

transverse process (TP) of L5.

 

48

Figure 5: Transducer position (curved,

phased array) and the needle insertion

plane to accomplish ultrasound- guided

lumbar paravertebral block in the

longitudinal view and an out-of-plane

needle insertion.

 

Figure 6: Simulated needle insertion

paths (1,2) to inject local anesthetics at

two different levels to accomplish a

lumbar paravertebral (LP) block. Needles

(1 and 2) are seen lodged about 2 cm

deeper and between the transverse

processes (TPs) using an out-of-plane

technique.

 

More recently, Karmakar and colleagues described the "trident sign

technique," which uses an easily recognizable ultrasonographic landmark,

transverse processes, and an out-of-plane needle insertion. The trident

sign technique derives its name from the characteristic ultrasonographic

appearance of the transverse processes (trident) to estimate the depth and

location of lumbar paravertebral space . After application of ultrasound

gel to the skin over the lumbar paravertebral region, the ultrasound

transducer is positioned approximately 3 to 4 cm lateral and parallel to

the lumbar spine to produce a longitudinal scan of the lumbar

49

paravertebral region (Figure 7). Then the transducer is moved caudally,

while still maintaining the same orientation, until the sacrum and the L5

transverse process become visible (Figure 8). The lumbar transverse

processes are identified by their hyperechoic reflections and acoustic

shadowing beneath which is typical of bone. Once the L5 transverse

process is visible, the transducer is moved cephalad gradually, to identify

the L3-L4 level. The goal of the technique is to guide the needle through

the acoustic window between the transverse processes (between the "teeth

of the trident") of L3-L4 or L2-L3 into the posterior part of the psoas

major muscle (Figure 2B). After obtaining ipsilateral quadriceps muscle

contractions, the block is carried out using the previously described

injection and pharmacology considerations (Figures 6 and 7).

Figure 7: Local anesthetic (LA) disposition during injection of local anesthetic into

the psoas muscle and the L2-L3 level. The spread of LA is often not well seen using

two-dimensional imaging. LP, lumbar plexus; TP, transverse process.

A paramedial scan also can be used with an in-plane needle approach.

In this technique, an insulated needle is inserted in-plane from the caudal

end (Figure 4) of the transducer while maintaining the view of the

transverse processes. Again, the goal is to pass the needle and inject local

50

anesthetic with a real-time visualization of the needle path and injection

into the posterior part of the psoas muscle (Figure 5).

In summary, ultrasound-guided PVB is a technically advanced

procedure. Experience with ultrasound anatomy and less technically

challenging nerve regional anesthesia techniques are useful to ensure

success and safety. Although the use of ultrasound in PVB is not widely

accepted, in expert hands, ultrasound guidance can increase the accuracy

and possibly safety, by providing information on the location,

arrangement, and depth of the osseous and muscular tissues of

importance in lumbar PVB. It should be kept in mind that the dorsal

branch of the lumbar artery is closely related to the trans-verse processes

and the posterior part of the psoas muscle.

Limitations of paravertebral block:

a) Considering the rich vascularity of the lumbar paravertebral area,

the use of smaller gauge needles and avoidance of this block in

patients on anticoagulants is prudent.

b) Injections into this area should be carried out without excessive

force because high-injection pressure can lead to unwanted

epidural spread and/or rapid intravascular injection.

c) In patients with obesity or advanced age, it can can be more

challenging. Aging is associated with a reduction in skeletal

muscle mass (sarcopenia) and replacement of the muscle mass by

adipose tissue, leading to changes in ultrasound absorption and

scattering.

51

Patients and methods

After local ethical committee approval and patient informed written

consent, this prospective randomized blinded clinical study was

conducted on 38 patients above 18 years old ASA I-III undergoing

elective inguinal herniorraphy and appendectomy under general

anesthesia. These patients will be randomly allocated by closed envelope

into two equal groups :-

Group PVB : Will receive in-plane ultrasound guided continuous

lumbar paravertebral block with 0.5% bupivacaine bolus dose followed

by continuous infusion of bupivacaine 0.125% with fentanyl 1mcg/ml.

Group EPB: Will receive continuous lumbar epidural analgesia with

0.5% bupivacaine bolus dose followed by continuous infusion of

bupivacaine 0.125% with fentanyl 1mcg/ml

Exclusion criteria:

1) Age < 18 years.

2) Coagulopathy.

3 (Patient uncooperation.

4 (Local sepsis

5 (anatomical deformity of the back.

6 (Allergy to local anaesthetic agent.

7 (Morbid obesity (BMI >35 kg m2).

8 (Neurologic disorders.

Preoperative visit :-

One day before surgery, a meeting was done with the patients to explain

visual analogue scale (VAS), ( a rating scale in which the patients mark

52

the location on the 10-centimeter line corresponding to the amount of

pain they experienced). This gives them the freedom to choose their

pain's exact intensity. Also routine investigations in the form of twelve

leads electrocardiography (ECG), complete blood count (CBC),

coagulation profile (bleeding time, prothrombine time, international

normalized ratio and partial thromboplastine time), liver functions, and

kidney functions were fulfilled.

)Figure 1:(Visual analogue scale (VAS)Verbal rating scale (VRS) and Numerical

rating scale (NRS)

General anaesthesia:-

Before the induction of general anaesthesia:

Intravenous access was established and IV fluids started, Monitoring of

the patients in the form of5-Lead ECG, Arterial Blood Pressure (Non

Invasive Blood pressure monitoring) and Pulse oximeter were conducted.

Prior to the regional block, IV access and arterial cannulation with local

anesthetic infiltration will be established and patients will be monitored

with electrocardiography, blood pressure monitoring (noninvasive), pulse

oximetry and capnogram.

53

Insertion of lumbar paravertebral catheter / lumbar epidural catheter

was done before induction of general anesthesia.

Induction of general anaesthesia:

After insertion of epidural/paravertebral catheters patients will be

turned supine. General anesthesia will be induced with IV fentanyl 1–2

mcg/kg, propofol 2–3 mg/kg followed by rocuronium 0.5–0.8 mg/kg to

facilitate endotracheal intubation.

Maintainance of general anaesthesia:

Anesthesia was maintained with Isoflurane 1.5% and rocuronium

0.15mg/kg as a maintainance dose every 30 minutes till the end of the

procedure. Ventilation parameters was adjusted as follows: TV = 7

ml/kg, respiratory rate = 12/min. and peak inspiratory pressure 30- 35 cm

H2O. End tidal CO2 was maintained between 35-40 mmHg.

Heart rate and mean arterial blood pressure (MAP) were monitored

throughout the operation and maintained within ± 20% of the

preoperative baseline by giving IV bolus doses of fentanyl approximately

1 mcg/kg if the MAP or heart rate increased more than 20% from the

baseline.

Recovery from general anaesthesia:

After the end of operation, reversal of neuromuscular blockade was

done by neostigmine 0.04-0.07 mg/kg and atropine 0.02 mg/kg. When

sufficient spontaneous breathing was established and the patient

responded adequately to instructions, the trachea was extubated after

gentle oropharyngeal suction. After emerging from anesthesia, the

patients was transferred to the post anesthesia care unit (PACU) for a 2

hours observation period .

54

Techniques of lumbar paravertebral block (PVB) :

A standard regional anesthesia tray was prepared with the following

equipment:

Sterile towels and 4"x4" gauze packs

20-mL syringes with local anesthetic .

Sterile gloves and marking pen.

One 1½" 25-gauge needle for skin infiltration

An 18 gauge 8 cm needle epidural set(Perifix.B.BRAUNMelsungen

AG).

Syringe pump(Fresenius Kabi) ,

GE LOGIQ P5 ultrasound machine

The lumbar paravertebral block (PVB) will be performed in the

preoperative area while the patient in the sitting position and leaning

forwards. After surgical disinfection of lumbar paravertebral areas with

protection of the ultrasound probe and cable with a sterile ultrasound

probe cover, the lumbar paravertebral space (LPVS) was identified with

ultrasound , using a5-8 MHz curved array ultrasound transducer

probe placed over a spinous process in the mid-line in a longitudinal

fashion . Once the best image of the interspace structures appeared,

Under sterile conditions,4-6 mL of local anesthetic (Lidocaine1 %) was

infiltrated subcutaneously alongside the line where the injections was

made . an 18 gauge 8 cm epidural needle(Perifix.B.BRAUNMelsungen

AG) was utilized for locating the paravertebral space

55

, The tip of the needle will be advanced under direct vision to

paravertebral space which is present at 6-8cm depth from skin surface in

lumbar region. Saline (3 mL) will then injected to:

a- demonstrate the position of injectate.

b- allow easier passage of the catheter, to a distance of 2-3 cm beyond

the needle tip.

An initial test dose of 3 mL of 2% lidocaine mixed with 1:200,000

epinephrine was injected followed by 0.5% bupivacaine(15-20ml) (0.3

mL/kg), administered over 10 minutes after recording arterial blood

pressure.

Technique of lumbar epidural block :

Epidural block will be performed in all patients in the sitting position

with binding forward and the legs are allowed to hang over the edge of

the bed with the feet supported by a stool. The shoulders are hunched

forward and the patient is encouraged to hug a pillow in towards the

abdomen to provide anterior flexion of the spine.Then anatomical land

mark will be identified by palpating the iliac crests that lie opposite the

disc between L4&L5. The skin surrounding this area will be sterilized by

povidone iodine solution and skin wheal will be infiltrated with local

anesthetic (Lidocaine 2%). using 22 gauge needle then the epidural

catheter 20 gauge will be placed at selected interspaced using midline

approach and saline loss of resistance technique through an 18-G touhy

epidural needle under complete sterile technique and directed

perpendicular to skin. Only 5 cm of the catheter will be left in the space

and the test dose (3ml Lidocaine 2%+1:200,000 adrenaline) will be

injected through the catheter to exclude subarachnoid and intravascular

56

catheter position. Epidural analgesia was done by using 0.5% bupivacaine

(5-8ml)( 0.1ml/kg) as loading dose.

In both groups continous infusion of bupivacaine 0.125% was started

at a rate of (0.1 ml/kg/hr) with fentanyl 1mcg/ml and maintained

throughout the period of the study(24 hours).

Hypotension was treated with intravenous ringer’s solution 15 ml/kg and

ephedrine 10 mg as needed to keep MAP more than 65 mm Hg.

Bradycardia ( HR < 60/ min.) was treated with atropine 0.01-0.02 mg/kg.

The following parameters were measured:

1-Demographic characteristics: Age in years, body mass index and ASA physical status.

2-Operative details: duration of surgery (time started from surgical incision till removal of surgical drapes).

3-Mean arterial blood pressure, heart rate at 0, 30 min, 1, 2, 6, 12, 24hr after the block.

4- respiratory rate and arterial oxygen saturation(Sao2) at 0,30 min, 1,2,6,12,24hr after surgery.

5-Postoperative pain level by 10-cm visual analogue scale(VAS) from 0 ( no pain) to 10 (unbearable pain) at 1, 2,6, 12, 24 hours after surgery. If VAS will be higher than 4, the infusion will be increased up to (10 ml/hr).

6- Pain rescue-analgesia consumption after 24 hours. If pain score exceed

4 despite the maximum infusion rate of bupivacaine, rescue analgesia

5mg bolus of morphine will be administered intravenous to achieve

satisfactory pain control, can be repeated every 4-6 hours.

57

Complications:

Postoperative nausea and vomiting, rescue antiemetics were offered to

any patient who complained of nausea or vomiting.

Sedation was measured by using Ramsay sedation scale (If Awake;

Ramsey 1: Anxious, agitated, restless, Ramsey2: Cooperative,

oriented, tranquil, Ramsey 3: Responsive to commands only. If

Asleep; Ramsey 4: Brisk response to light glabellar tap or loud

auditory stimulus, Ramsey 5: Sluggish response to light glabellar tap

or loud auditory stimulus) the presence of sedation was defined as a

sedation scale >2 at any postoperative time point.

Pruritus.

Complications related to the block technique.

The study ended 24 hours after the operation.

Statistical analysis: Analysis of data will be done by using SPSS (statistical program for

social science version 16) as follows:

Description of quantitative variables as mean and standard deviation.

Description of qualitative variables as number and percentage.

Unpaired student t-test will be used to compere the quantitative

variables between groups.

45Chi-square test will be used to compare qualitative variables

between groups.

P < 0.05 will be considered significant.

P < 0.01 will be considered highly significant.

Sample size calculation:

Considering pain rescue-analgesia consumption as the primary

outcome, and taking α error = 0.05 (confidence interval = 95%)

58

and the power of test (1-β) as 80%. Sample size was calculated

from previous study was done by Wardhan et al, (2014). We

considered that a reduction more than 25 % in morphine

consumption will be satisfactory (The effect size was 0.96).

Thus, we recruited 38 patients for randomization (19 patients in

each group).

59

Results

This study was conducted on 38 patients underwent unilateral lower

abdominal surgery (inguinal herniorraphy and appendectomy). Patients

were divided into two equal groups:

Group I ( PVB ): received in-plane ultrasound guided continuous

lumbar paravertebral block with 0.5% bupivacaine bolus dose followed

by continuous infusion of bupivacaine 0.125% with fentanyl 1mcg/ml.

Group II (EPB): received continuous lumbar epidural analgesia with

0.5% bupivacaine bolus dose followed by continuous infusion of

bupivacaine 0.125% with fentanyl 1mcg/ml.

As regards age, weight, height, BMI and ASA status, there was no

significant differences between both groups (P>0.05).

Average age was 41.21y in group (PVB) and 43.84y in group (EPB) and

p- value=0.29

Average weight was 49.95kg in group (PVB) and 49.42kg in group

(EPB) and p- value = 0.91

Average height was 160.4cm in group (PVB) and 159.93cm in group

(EPB) and p- value = 0.76,

Average BMI was 27 kg/m2 in group (PVB) and 27.63kg/m2 in group

(EPB) and p- value = 0.47,

Average duration of surgery was 74.37min in group (PVB) and 77.84min

in group (EPB) and p-value = 0.27

60

Table (1 (:- Demographic data and duration of surgery

Group I (PVB) Group II (EPB)

Test of significance

p- value

Age(years) 41.21±7.68 43.84±7.29 t=1.08 0.29Weight(Kg) 49.95±15 49.4

2±13.96t=0.11 0.91

Height(Cm) 160.4± 5.66 159.93 ± 6.12

t=0.31 0.76

BMI(kg/m2) 27.01±2.2 27.63±2.96 t=0.73 0.47Duration of

surgery(min)74.37±15.24 7.84±18.24 t=1.2 0.24

ASA Status I 8 6X2 =0.5 0.7II 8 10

III 3 3

Data were presented as mean ± SDASA status data were presented as numbers and percentageP – Value < 0.05 was considered statistically significant

Type of surgery:

As regards comparison of type of surgery between both groups, there was

no significant difference in the type of surgery between both groups.

(Table 2): type of surgery in both groups

Type of surgery Group I (PVB) Group II (EPB)

Test of significance

p- value

Inguinal hernia 15 16x2=0.18 p=0.9 appendectomy 4 3

Data were presented as numbers and percentage

Visual Analogue Scale (VAS)

VAS was measured at rest and on patient's movement (knee flexion), at1,2,6,12 and 24 hours postoperative (table3)

61

Table (3):-visual analogue score (VAS) of both groups

Post-operative Group I (PVB)

Group II (EPB)

Test of significance

p-value

1hr At rest 4 ±3 3 ±1.62 t= 1.607 0.114On

movement4.37 ± 1.88 4.1 ± 1.81 t= 0.567 0.573

2hr At rest 2.73 ±1.68 2.06 ±1.20 t= 1.778 0.081On

movement3.7 ± 1.95 3 ± 1.41 t=1.593 0.117

6hr At rest 2.4 ±1.40 2 ±1.08 t= 1.201 0.235On

movement3.4 ± 1.57 3.07 ± 1.36 t=0.870 0.388

12hr At rest 2.2 ±1.21 2 ±1.17 t= 0.651 0.518On

movement2.4 ± 1.25 2.03 ± 0.99 t=1.271 0.209

24hr At rest 1.43 ±1.28 1 ±0.91 t= 1.499 0.139On

movement2.33 ± 1.18 2 ± 0.98 t=1.178 0.244

Data were presented as mean ± SD

Current study showed insignificant differences between both groups as regards VAS either at rest or on patient's movement as shown in fig.(1) and fig.(2)

At 1hr post-operative, there was insignificant difference between both groups as regards VAS both at rest(p=0.114) and on patient's movement (p=0.573).

At 2hrs post-operative, there was also insignificant difference between both groups as regards VAS both at rest (p=0.081) and on patient's movement (p=0.117).

62

At 6hrs post-operative, there was insignificant difference between PVB and EPB groups as regards VAS both at rest (P=0.235) and on patient's movement (p=0.388).

At 12hrs post-operative, there was also insignificant difference between both groups as regards VAS both at rest (p=0.518) and on patient's movement (p=0.209).

At 24hrs post-operative, there was also insignificant difference between both groups as regards VAS both at rest (p=0.139) and on patient's movement (p=0.244).

VAS R 1 VAS R 2 VAS R 6 VAS R 12 VAS R 240

0.5

1

1.5

2

2.5

3VAS at rest

PE

Fig. (1) :- VAS values at rest

63

VAS M 1 VAS M 2 VAS M 6 VAS M 12 VAS M 241

1.5

2

2.5

3

3.5VAS at movement

PE

Fig.(2):VAS values on patient's movement

Total pain rescue-analgesia consumption during 24 hours:

As regards total morphine consumption in the first post-operative 24

hours (5 mg morphine were given as bolus dose when VAS exceeds 4

despite the maximum infusion rate of bupivacaine),the current study

showed no statistically significant difference (p>0.05) between PVB and

EPB groups.

Table (4) :- Total pain rescue-analgesia consumption during 24 hours (mg/24h)

Groups Group PVB Group EPB Test of of

significance

P - value

Total-analgesia

consumption (mg morphine/24 h)

6.84 ± 2.48 6.58 ±2.91 0.30=t0.77

64

Group P Group E6

8

Fig.(3): Total analgesic consumption during 24 hours (mg morphine/24 h)

Mean arterial blood pressure (MAP) -:

As regards comparing mean arterial blood pressure (MAP) between

both groups ;Current study showed statistically highly significant change

in MAP in EPB group as compared with PVB group at1,2,6,12 and 24hr

postoperative as shown in table(5)

(Table 5):mean arterial blood pressure (MAP) of both groups in mmHg

MAP (mmHg)

Group I (PVB)

Group II (EPB)

Test of significant

p- value

Base line 78.95±5.31 80.84±3.25 t=1.33 0.191 hrs. 77.11±4.46 70.05±4.45 t=4.88 0.001** >2 hrs. 76.26±4.78 69.16±3.95 t=4.99 0.001** >6 hrs. 78±3.94 71.42±4.46 t=4.81 0.001** >

12 hrs. 79.11±2.16 75.32±2.79 t=4.68 0.001** >24 hrs. 880.4

2±2.4173.25±2.41 t=8.75 0.001** >

Data were presented as mean ± SD*significant **highly significant

65

MAP at 1hr showed highly significant difference between both groups (p<0.001),Also at 2hrs, there is high significant difference in MAP between PVB and EPB groups (p<0.001),At 6hrs, there is high significant difference in MAP between both groups as p<0.001At 12hrs, MAP showed high significant difference in PVB and EPB groups (p<0.001).Also there was high significant difference in MAP at 24hrs post-operative between PVB and EPB groups.

MAP0 MAP1 MAP1 MAP2 MAP6 MAP12 MAP2460

65

70

75

80

85

MAP

Group PGroup E

Fig.(4): MAP values in all groups (mm Hg)

Heart rate (HR) -:As regards heart rate(HR) in both groups ,current study showed

insignificant decrease in heart rate in EPB group as compared with PVB

group at 1,2,6 and 12hrs post-operative.

Table (6):-Heart rate (HR) of both groups

HR (beat/min)

Group I (PVB)

Group II (EPB)

Test of significant

p- value

66

Base line 79.84±3.27 80.26±2.68 t= 0.43 0.671 hrs. 79.64±2.67 78.61±2.59 t= 1.79 0.062 hrs. 78.53 ±

2.0176.68 ± 2.21

t= 3.63 0.01*

6 hrs. 79.32 ± 2.77

77.47 ± 2.95

t= 1.98 0.05*

12 hrs. 79.32 ± 2.77

77.47 ± 2.95

t= 1.98 0.055

24 hrs. 78.74 ± 3.03

79.79 ± 2.49

t= 1.17 0.25

Data were presented as mean ± SD*significant **highly significant

0 1 2 6 12 2476

76.5

77

77.5

78

78.5

79

79.5

80

80.5

81

Group EGroup P

Fig.(5):-heart rate(bpm)

At 1hr post-operative, there was insignificant decrease in heart rate in

EPB group (p>0.05).

Also at 2hrs, there was significant decrease in heart rate in EPB group as

compared toPVB group (p=0.01).

At 6hrs, there was significant decrease in heart rate in EPB group

(p<0.05).

Heart rate showed insignificant decrease in EPB group as compared to

PVB at 12hrs post-operative (p>0.05).

67

At 24hrs, there was insignificant increase in heart rate in EPB group

(P=0.25).

Respiratory rate:- As regards respiratory rate (RR) in the two groups, current study showed

no statistically significant differences in RR between both groups as

shown in fig.(6)

Table (7):-Respiratory rate values\min

RR Group I (PVB)

Group II (EPB)

Test of significant

p- value

Base line 18.05±1.51 17.84±1.26 0.467 0.6431 hrs. 18.32±0.95 18.37±1.01 0.165 0.8692 hrs. 18.26±1.51 18.21±1.01 0.145 0.8856 hrs. 18.42±1.02 18.26±1.05 0. 274 0.640

12 hrs. 18.32±0.95 18.47±1.02 0.494 0.62324 hrs. 18.42±0.96 18.11±1.10 0.942 0.352

68

0RR 1RR 2RR 6RR 21RR 42RR71

81

91

RR

1seireS2seireS

Fig.(6): - Respiratory rate values in both groups during 24 hours

At 1hr post-operative, mean RR was 18.32 in PVB group and 18.37 in EPB

group i.e. no significant difference between the two groups.

At 2hr, mean RR was 18.26 in PVB group and 18.21 in EPB group .

At 6hr, mean RR was 18.42 in PVB group and 18.26 in EPB group.

At 12hr, mean RR was 18.32 in PVB group and 18.47 in EPB group.

At 24hr, mean RR was 18.42 in PVB group and 18.11 in EPB group.

Complications

As regarding complications during the study in all groups,

complications as nausea , vomiting , pruritis and drowsiness were recorded ,

table(9).

Nausea: - Regarding nausea in both groups, there were 4 patients (21.05%)

in group EPB and 1 patient (5.3%) in group PVB. These results are

statistically non significant (p=1)

69

Vomiting: - As regards incidence of vomiting in both groups , there were 3

patients ( 15.8%) in group EPB and 0 patient (0 %) in group PVB .p=1 this

means that results are statistically insignificant.

Pruritis :- The incidence of pruritis was 2 patients (10.5%) in group P , and 1

patient (5.3 %) in group E. these results are statistically insignificant as p=1.

Drowsiness :- Regarding drowsiness in both groups , number of patients

complaining in group PVB was 2 patients (10.5%) and in group EPB there

was one patient ( 5.3%) . p=1 so the results are insignificant.

Urine retention:-There were 6 patients (31.05%) complaining of urine

retention in group EPB and 0 patients(0%) in group PVB .p-value <0.05 i.e.

there was significant difference between the two groups as regards urine

retention.

Table (8): complications in both groups

Complications Group P Group E P Value

Nausea 1 (5.3%) 4 (21.05% ) 0.15

Vomiting 0 ) 0(% 3 ) 15.8( % 0.07

Pruritis 2 ) 10.5(% 1 ) 5.3(% 0.55

Drowsiness 2) 10.5(% 1 ) 5.3(% 0.55

Urine retention 0(0%) 6( 31.05%) 0.04

70

Data were presented as numbers and percentage

*significant

pain is a stressor that can threaten homeostasis (a steady physiological

state). The adaptive response to such a stress involves physiology

changes that, in the initial stages, are useful and are also potentially life-

saving (Bultaci, 2007 ).

Unrelieved postoperative pain may result in clinical and psychological

changes that increase morbidity, mortality, costs as well as decrease

quality of life and potentially increase the incidence of chronic pain.

Negative clinical outcomes resulting from ineffective postoperative pain

management include deep vein thrombosis and pulmonary embolism,

coronary ischemia and myocardial infarction, pneumonia, poor wound

healing, insomnia and demoralization. Associated with these

complications are economic and humanistic implications such as

extended lengths of stay, readmissions, and patient dissatisfaction with

medical care. A recent study suggests that pain in ambulatory surgical

patients is still undermanaged and the incidence of moderate to severe

pain remains high (Apfel AL et al., 2003).

71

As regarding our study, it was held at Benha university hospital to

compare the efficacy of continuous lumbar epidural block versus

ultrasound guided continuous lumbar paravertebral block on

perioperative analgesia and haemodynamic stability in patients

undergoing lower abdominal surgery in a prospective, randomized study.

38 patients were included in this study (19 patients in each group).there

were no differences between them as regarding demographic

characteristics (age, weight, height, BMI), type and duration of surgery.

The primary outcome measure: is the mean morphine consumption in

the first 24 hours postoperative and visual analogue scale ( VAS).

The secondry measures include: age, weight, height, BMI, ASA, vital

signs (MAP, HR, RR), type and duration of surgery and complications

(nausea, vomiting, pruritis, drowsiness and urine retention).

As regards visual analogue scale (VAS) that was measured both at rest

and on patient's movement at 1,2,6,12 and 24 hours post-operative, there

was insignificant difference between both groups although it was slightly

lower in EPB group.

Also there was insignificant difference in total morphine consumption in

the first post-operative 24 hours.

These results goes with( Pankaj N Surange and Brig Chadalavada

Venkata Rama Mohan 2012 )who compared Continuous Lumbar

Paravertebral Versus Continuous Epidural Block in patients undergoing

hip Surgery where 60 patients were randomly allocated into two groups

of 30 subjects:

72

1. Group I: 5 mL/h, 0.125% bupivacaine, continuous paravertebral

group.

2. Group II: 5 mL /h, 0.125% bupivacaine, continuous epidural

group.

Then 2.5-3ml of 0.5%bubivacaine injected intrathecal. the patients were

observed for 48hours after surgery and no statistical significant

differences were found between the two groups in VAS either at rest or

on exercise (active and assisted hip flexion and extension against

gravity). Other study done by (Hazem Ebrahem Moawad et al., 2013)

who performed a prospective randomized study to compare between

paravertebral and epidural block after open renal surgery. Mean

postoperative VAS scores demonstrated no significant difference between

both groups throughout the duration of monitoring(24 hours) .The total

analgesic consumption (meperidine) at 24 h postoperatively also showed

no significant difference between the two groups. After 24 h, all patients

had the worst pain with VAS score 4 mm in the EP group, versus 5 mm

in the PVB group. ( G. Türker et al., 2003) performed a study for

Comparison of the catheter-technique psoas compartment

(paravertebral)block where 30 ml of 0.5%bupivacaine was injected in the

paravertebral space and the epidural block by injection of 15ml of

0.5%bupivacaine in the epidural space for analgesia in partial hip

replacement surgery. Ten minutes before the end of the operation, each

patient was connected to a patient-controlled analgesia device set to

deliver an infusion of 0.125% bupivacaine and 2 µg/ ml fentanyl at a rate

of 10 ml/ h, in addition to 5-ml boluses for post-operative analgesia. The

groups were similar regarding pain scores (at rest and on movement) and

patient satisfaction. An updated metaanalysis was done by (Xibing Ding

et al., 2014) to compare analgesic efficacy and side effects of

73

Paravertebral Compared with Epidural Blockade for Thoracotomy. There

was no statistically significant difference in pain scores between the PVB

and EPI groups at postoperative 4–8 h, at 24h or at 48h ). There was also

no significant difference in morphine consumption between the two

groups at postoperative 24 h .Another study for comparing between

epidural and paravertebral blocks in patients undergoing thoracotomy

was done by( O Cucu et al.,2004). All patients received a bolus

dose of %0.25 bupivacaine 10 ml before wound closure and a infusion of

%0.25bupivacaine 0.1ml/kg/ hr was started immediately upon arrival to

surgical intensive care unit and continued for 24 hours. There were no

significant differences between the groups with respect to VAS scores at

any point of observation. The mean pain scores were 52.40±21.50 and

44.40±19.40 in epidural and paravertebral groups respectively in the

immediate postoperative period at rest and whereas at 4 th hour they were

decreased to 30±14.10 and 27.20±13.40. In both groups pain scores were

significantly lower compared to immediate postoperative period on all

occasions of measurement. There were no statistically significant

differences between the groups in morphine consumption, 37.56±25.93

mg and 36.78±18.58 mg (p = 0.903) for epidural and paravertebral groups

respectively.

Debreceni et al., 2003 who studied the comparison between

Continuous epidural and paravertebral analgesia following thoracotomy .

They founded that pain management with continuous epidural analgesia

was superior to continuous paravertebral analgesia, in the early

postoperative period. The statistically significant difference in the VAS

scores between the two groups (up to 12hr postoperative only), in favor

of the epidural technique, this can be explained by; the large volume

injected into the epidural space (0.2 ml/kg).

74

Our study does not go with( Antipin, E et al., 2014) who compared

between lumbar paravertebral and lumbar epidural blocks as methods of

analgesia in the first stage of labour : A prospective randomized study of

nulliparous women included three groups of patients: the group of 30

patients with EA (0.15% ropivacaine + fentanyl 2 µg/ml); the PVB group

of 30 patients (0.75% ropivacaine 10 ml bilaterally); the control group of

30 patients . The severity of pain at the opening of the cervix was

completely alleviated from the maddening group EA (VAS 82,6 ± 1,9

mm) and PVB (VAS 83,2 ± 1,7 mm) to a small (5,2 ± 0,9) and ( 14,5 ±

1,8), respectively. this is most probably due to higher concentration of

ropivacaine used in PVB group(0.75) versus (0.15)in EPB group.

As regards mean arterial pressure (MAP) in our study, there was slight

decrease in MAP AT 1,2,6 and 12 hours from base line in PVB group

while in EPB group there is marked decrease in MAP at 1,2,6,12 and 24

hours from baseline and statistical analysis between both groups was

highly significant(p<0.001).

As regards heart rate (HR) change in our study, there was insignificant

decrease in (HR) in PVB group and significant decrease in EPB group.

statistical analysis showed significant difference in HR between both

groups at 2 hr postoperative (p=0.01).

These results goes with a prospective randomized study done by

(Hazem Ebrahem Moawad et al., 2013) who compared paravertebral

block versus epidural block in open renal surgery. They found a

significant decrease in MAP in EPB group compared with PVB group 15

min, 30 min, 1 h, 1½, and 2 h from the start of surgery (P<0.001).

similarly , there was a significant decrease in HR in EPB group compared

75

with PVB group at 2, 2½, 3, and 3½ h and at 30 min, 12 h,16 h, and 24 h

postoperatively (Pranged from <0.01 to <0.001).

Regarding Pankaj N Surange and Brig Chadalavada Venkata

Rama Mohan ,they performed a study ion 2012 named Comparative

Evaluation of Continuous Lumbar Paravertebral Versus Continuous

Epidural Block for Post-Operative Pain Relief in Hip Surgeries. The

preoperative heart rate (HR) and MAP of all patients were recorded

before the procedure was performed. Subsequent readings were taken

every 5 minutes. Intraoperatively after spinal anesthesia and thereafter

recorded at 2, 4, 8, 12, 18, 24, 32, 40 and 48 hours.

There mean arterial pressure was significantly lower in the epidural

group compared with the paravertebral group from 2 hours after the

infusion was begun to 48 hours. Regarding the heart rate,it was not like in

our study as it was higher in the epidural group throughout the study

period, albeit insignificantly. In a study done by( G. Tu'rker., et al

2003)involving thirty patients undergoing total hip replacement surgery

where psoas compartment block was done in fifteen patients (group P)

and epidural block in the other fifteen(group E).Hemodynamic

parameters(MAP and HR) were recorded every 10 minutes

intraoperative. . Group E showed significantly greater drops in mean

arterial blood pressure from baseline at 30, 40 and 50 min after the start

of general anesthesia. Significantly more Group E patients required

epinephrine supplementation. In an updated meta-analysis done

by( Xibing Ding et al., 2014) to compare analgesic efficacy and side

effects of paravertebral compared with epidural blockade in thoracotomy

patients , PVB was associated with less hypotension.In another study

done by (O Cucu et al., 2005) in thoracotomy patients to compare

epidural anaesthesia and paravertebral block, heart rate and MAP were

76

significantly lower in epidural group at postoperative 6 th,12th and 24

hours as compared to paraverteral group (p<0.01). Intragroup

comparisons showed that, in epidural group MAP decreased significantly

at all points of measurements compared to preinduction values (p<0.01).

Also MAP at 6 h hours was found to be lower than the one measured

after 20 minutes of bolus dose. Parallel to that, heart rate also was also

found to be lower at all points of observations compared to preinduction

and postbolus values in epidural group, In paravertebral group, although

not as much as epidural group, heart rate was also found to be lower at all

occasions as compared to prenduction values (p<0.05) .

As regards complications in our study, they include nausea, vomiting,

pruritis, drowsiness and urine retention .there were 1 patient(5.3%)in

group PVB and 4 patients(21.05%)in group EPB complaining of nausea,

0(0%) in PVB and 3(15.8%)patients in EPB complaining of vomiting ,

2(10.5%)patients in PVB group and 1(5.3%)patients in EPB group

complaining of pruritis and drowsiness, 0(0%)patient in PVB group and

4(21.05%)patients in group EPB suffering from urine retention. These

results are statistically insignificant.

Our study goes with (Pankaj N Surange and Brig Chadalavada

Venkata Rama Mohan 2012) who concluded that paravertebral block is

technically simple and easy to learn with few contraindications, provides

hemodynamic stability, and has a low complication rate and is therefore a

safe and effective technique in controlling postoperative pain after

unilateral hip surgery.

In a prospective randomized study done by (Hazem Ebrahem

Moawad et al., 2013), Postoperative shivering developed in 2 patients in

each group. Whereas 3 patients in EP group suffered from nausea

77

postoperatively compared with 2 patients in the PVB group. In a study

performed by (G. Turker et al., 2003) There were no differences

between the two groups regarding catheter-related problems. Orthostatic

hypotension, urinary retention, and nausea-vomiting were also

significantly more frequent in Group E (P<0.05, P<0.01 and P<0.05,

respectively).In the study done by( Xibing Ding .,et al 2014) to compare

analgesia and side effects of paravertebral versus epidural blockade in

thoracotomy patients, PVB resulted in significantly less incidence rates of

urinary retention (OR 0.21, 95%CI: 0.10 to 0.44; I2 = 0%; p<0.0001),

nausea and vomiting (OR 0.49, 95% CI: 0.28 to 0.87; I2 = 27%, p = 0.01),

and hypotension (OR 0.11, 95% CI: 0.05 to 0.25; I2 = 

0%, p<0.00001)compared to EPB. Rates of failed technique were lower

in the PVB group (OR 0.51, 95%CI: 0.30 to 0.86; I2 = 29%; p = 0.01).

However, there was no significant difference in pulmonary complications

(OR 0.51, 95% CI: 0.23 to 1.11); I2 = 0%; p = 0.09. In another study done

by (O Cucu et al., 2005) in patients with thoracotomy, 3 patients in

epidural and 2 patients in paravertebral group experienced at least one

nausea and vomiting episode graded as severe and they were given

ondansetron (p=1). Two patients in each group reported nausea episode

graded as mild and they were not given any medication. urine retention

could not be assessed as Foley catheters had been routinely inserted at the

time of surgery.

Limitations of the study:

One of the possible shortcomings of our study; the study did

not include a placebo control group.

The study limited assessment of postoperative analgesia to

the first 24 postoperative hours.

78

However, the blocks demonstrated to produce satisfactory levels of

analgesia for at least 48 hours.

Conclusion

Our study showed that both continuous epidural and continuous

paravertebral blocks are effective in controlling postoperative pain after

lower abdominal surgeries with lower rate of complications (hypotension,

bradycardia, nausea, vomiting and urine retention) in paravertebral group.

79

pain is a stressor that can threaten homeostasis (a steady physiological

state). The adaptive response to such a stress involves physiology

changes that, in the initial stages, are useful and are also potentially life-

saving.

Unrelieved postoperative pain may result in clinical and psychological

changes that increase morbidity, mortality, costs as well as decrease

quality of life and potentially increase the incidence of chronic pain.

Negative clinical outcomes resulting from ineffective postoperative pain

management include deep vein thrombosis and pulmonary embolism,

coronary ischemia and myocardial infarction, pneumonia, poor wound

healing, insomnia and demoralization. Associated with these

complications are economic and humanistic implications such as

extended lengths of stay, readmissions, and patient dissatisfaction with

medical care. A recent study suggests that pain in ambulatory surgical

patients is still undermanaged and the incidence of moderate to severe

pain remains high.

80

Aim of the study: This study was done to evaluate efficacy of both

continuous lumbar epidural and ultrasound guided continuous

paravertebral block on perioperative analgesia and hemodynamic stability

in patients undergoing lower abdominal surgery.

Patients and methods: this prospective randomized blinded clinical

study was done on 38 patients above 18 years who were randomized into

two equal groups:

-group PVB:(19 patients received in-plane ultrasound guided continous

lumbar paravertebral block with 15-20 ml(0.3ml/kg) of 0.5% bupivacaine

bolus dose followed by continuous infusion of bupivacaine 0.125% with

fentanyl 1mcg/ml.

-group EPB:(19 patients received continuous lumbar epidural analgesia

with 5-8 ml(0.1ml/kg) of 0.5% bupivacaine bolus dose followed by

continuous infusion of bupivacaine 0.125% with fentanyl 1mcg/ml.

After insertion of epidural/paravertebral catheters patients were turned

supine. General anesthesia was induced with IV fentanyl 1–2 mcg/kg,

propofol 2–3 mg/kg followed by rocuronium 0.5–0.8 mg/kg . Anesthesia

was maintained with Isoflurane 1.5% and rocuronium 0.15mg/kg as a

maintainance dose every 30 minutes till the end of the procedure.

Ventilation parameters was adjusted as follows: TV = 7 ml/kg,

respiratory rate = 12/min. and peak inspiratory pressure 30- 35 cm H2O.

End tidal CO2 will be maintained between 35-40 mmHg.heart rate and

MAP were monitored.

The primary outcome measure: is the mean morphine consumption in

the first 24 hours postoperative and visual analogue scale ( VAS).

81

The secondry measures include: age, weight, height, BMI, ASA, vital

signs (MAP, HR, RR), type and duration of surgery and complications

(nausea, vomiting, pruritis, drowsiness and urine retention).

Results: there was insignificant differences between epidural and

paravertebral groups as regarding VAS and total morphine consumption

in the first post-operative 24 hours.

As regarding MAP and HR, they were lower in epidural group.

complications including nausea, vomiting and urine retention were higher

in epidural group.

Conclusion: both continous epidural and continous paravertebral blocks

are effective in controlling postoperative pain after lower abdominal

surgeries with lower rate of complications (hypotension, bradycardia,

nausea, vomiting and urine retention) in paravertebral group.

82

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العربى الملخص

للألم الجسم بدايتها يستجيب فى تعد فسيولوجية بطريقةنافعةومفيدة.

اكلينيكيا يؤثر الجراحية العمليات مابعد معالجةآلام عدم كماأنمعدلات وزيادة زيادةالتكلفة إلى ممايؤدى المرضى على ونفسيا

. إلى أيضا كمايؤدى المزمنة الآلام حدوث نسبة وازدياد الوفاة , ذبحة حدوث بالأوردة الدم تخثر مثل السلبية الآثار من العديد

, , القلب, بعضلة الدم تجلط الرئوى بالشريان الدم تجلط صدرية. الأرق و الجروح التئام عدم و رئوى التهاب حدوث

مدة إطالة إلى يؤدى إذ الاقتصادية الناحية من سلبيا يؤثر أنه كماخروجه بعد المستشفى إلى المريض عودة أو بالمستشفى الإقامة

. له المقدمة الطبية الرعاية عن المريض رضاء عدم و منها

89

مع التعامل فى قصور وجود إلى حديثا أجريت دراسة أشارت وقدبين ما شدتها تتراوح التى و الجراحية العمليات مابعد آلام

. شديدة إلى متوسطة

: الدراسة من الهدفطريق عن التخدير فاعلية بين المقارنة إلى الدراسة هذه تهدفبجانب المستمر الحقن و الجافية الأم فوق المستمر الحقنتخفيف فى الصوتية فوق الموجات باستخدام القطنية الفقراتالحيوية العلامات استقرار و السفلى البطن عمليات بعد الألم

للمرضى.: البحث وطريقة المرضى

على الدراسة هذه فوق 38أجريت أعمارهم تم, 18مريض عامامنهما كل تحتوى متساويتين مجموعتين إلى عشوائيا تقسيمهم

مريضا :19على : الفقرات بجانب المستمر للحقن خضعت الأولى المجموعة) , إعطاؤها تم الصوتية فوق الموجات باستخدام مل)20-15القطنية

البيوبيفاكين عقار .0.5من أولية% كجرعة , : وتم الجافية الأم فوق المستمر للحقن خضعت الثانية المجموعة

البيوبيفاكين) 8-5إعطاؤها ( ر غقا من .0.5مل أولية% كجرعةعيار ( قسطرة وضع تم المجموعتين كلتا المستمر) 20في للحقن

/ 0.1بمعدل البيوبيفاكين/ عقار من ساعة كجم عقار% 0.125مل معبمعدل للتخدير/ 1الفنتانيل المريض إخضاع تم ثم مل ميكروجم

الكلى .ثم الكلى التخدير من المريض إفاقة تم الجراحية إنهاءالعملية بعد

العلامات لمتابعة الجراحية عمليات بعد ما الرعاية لوحدة نقل. المستمر الحقن استمرار مع لمدةساعتين الحيوية

عند الآتية المعايير قياس تم :24,12,6,2,1ثم الإفاقة بعد ساعة

90

1) لايوجد) صفر من تتراوح والتى البصرى بالمقياس الألم شدة( محتمل) ( غير ألم عشرة إلى ألم

خلال) 2 المسكنة المواد استهلاك ساعة24معدلالقلب) 3 ضربات ومعدل الدم ضغط متوسطالتنفس) 4 معدل

: البحث نتائجبالنسبة الدراسة مجموعتى بين واضح فرق وجود ملاحظة يتم لم

المسكنة المواد استهلاك أومعدل البصرى بالمقياس الألم لشدةساعة.24خلال

كانوا فقد القلب ضربات ومعدل الدم ضغط لمتوسط أمابالنسبة. الجافية الأم فوق حقنها تم التى المجموعة فى أقل

( , , ) كانت فقد البول احتباس القئ الغثيان للمضاعفات وبالنسبة. الجافية الأم فوق حقنها تم التى المجموعة فى أكثر أيضا

الجافية الأم فوق المستمر الحقن من كلا أن ذلك من ونستنتجمابعد لآلام فعال علاج القطنية الفقرات بجانب المستمر والحقن

. الجراحية العمليات

91